Drying device for freshly printed sheets



Dec. 3, 1968 w, KOCH ETAL 3,413,732

DRYING DEVICE FOR FRESHLY PRINTED SHEETS Filed May 10, 1967 4Sheets-Sheet 1 Fig. I

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DRYING DEVICE FOR FRESHLY PRINTED SHEETS Filed May 10, 1967 4Sheets-Sheet 2 Fig. 2

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Dec. 3, 1968 w. KOCH ETAL DRYING DEVICE FOR FRESHLY PRINTED SHEETS 4Sheets-Sheet 4 Filed May 10, 1967 5 M 5 n QMY Q s a. V u 4 F a x YM \W wA m mm b a I m w w nkl 3,413,732 DRYING DEVICE FOR FRESHLY PRINTEDSHEETS Werner Koch, Gotzenhain, and Friedrich Preuss, Neu- Isenburg,Germany, assignors to Roland Olfsetmaschinenfabrik Faber & SchleicherA.G., Offenbach am Main, Germany, a firm of Germany Filed May 10, 1967,Ser. No. 637,443 Claims priority, application Germany, May 21, 1966, R43,315- 7 Claims. (Cl. 34-162) ABSTRACT OF THE DISCLOSURE A device fordrying printers ink on freshly printed sheets printed in a printingpress and before being transported, one by one, to a treatment station.The device includes substantially vertically disposed up and down dryingpaths along which the sheets to be dried are guided by endlessconveyors. The device also includes means for restoring moisture lost bythe sheets while being dried, for instance, by hot air. Such verticaldisposition of the drying paths reduces the space required for thedevice so that the same can be conveniently installed between theprinting assembly of the press and the treatment station.

The invention relates to a device for drying the printers ink on sheetsfreshly printed in the printing assembly of a printing press, and moreparticularly, to a drying device in which the freshly printed sheets aregripped at the leading edges by suitable grippers and are transported byendless conveyors along a straight path to a further treatment station.

With drying devices of this kind it is obviously important that thefreshly printed surface is not smeared when and while the sheets aretransported to the further treatment station such as a station in whichadditional operations are performed on the sheets. It is also essentialthat bending or other dislocation of the sheets is avoided. Moreover, itis desirable that the sheets are dried as quickly as possible so thatthere is little or no waiting time before further operations on thesheets can be effected, for instance, by a sheet folding machine.

It has been proposed to powder the freshly printed sheets with lime dustor similar powders. However, a machine in which powdered sheets areprocessed is bound to become dirty and the sheets themselves also tendto become smudged by the powder.

As is evident, rapid drying of freshly printed sheets has severaladvantages. It also tends to enhance the brilliance and clarity of theprint. I

However, no nearly satisfactory sheet drying device is available as yet.It is known to interpose between the printing unit of a letter pressperfecting rotary printing press a drying device through which thefreshly printed sheets are moved along a horizontal path by an endlessconveyor. Such drying devices are full disclosed, for instance, inPatent 2,174,865. Drying devices of this kind have the disadvantage thatthey very much increase the total length of the printing installation.In particular, with high speed printing presses the drying pathsrequired for adequate drying of the sheets must be so long due to thehigh speed with which sheets are delivered to the paths that the devicebecomes impractical for reasons of space.

It is a broad object of the present invention to provide a novel andimproved sheet drying device in which drying paths of adequate lengtheven for use in conjunction with high speed presses can be accommodatedin a comparatively small space.

It is also an object of the invention to provide a novel ted StatesPatent 3,413,732 Patented Dec. 3, 1968 and improved drying device inwhich each sheet is gripped so that it is guided along the drying pathsof the device in fixed positions in reference to preceding andsubsequent sheets and in reference to the paths thus avoiding smearingof the sheets by contact with each other while they are still wet andassuring uniform drying of the sheets.

A further object of the invention is to provide a novel and improveddrying device which is associated with means for restoring moisture lostby the sheet material during the drying operation so that the normalpliability and strength of the sheet material are preserved.

The afore-pointed out objects, features and advantages and otherobjects, features and advantages of the invention will be pointed outhereinafter, are attained by providing drying conveyor means which guidethe sheets to be dried up and down along substantially verticallydisposed drying paths and by further providing gripper means grippingthe leading edge and the trailing edge of each sheet as the same arrivesat the drying device. Such gripping of the sheets at both edges preventsfluttering of the rear parts of the sheets as they pass through thedrying device and thus smearing of the sheets and localized warmingthereof. As is evident, vertical up and down drying paths require muchless space than would be required by a straight drying path of the sametotal length but horizontally disposed.

Another aspect of the invention is to provide a heating means adjacentto the run of the conveyor means leading the sheets upwardly and acooling means adjacent the run of the conveyor means leading the sheetsdownwardly in the drying device. Stationary guide bars supporting thesheets on the dry side thereof while the sheets pass through the dryingdevice may be provided. The guide bars are preferably so mounted thatthe heat losses caused by the bars are reduced to a minimum.

The rotary components of the conveying means of the device arepreferably mounted on the side of the guide bars distant from theheating means and the cooling means so that the rotary components arewell protected against large temperature gradients.

The invention also contemplates to provide a dampening device posteriorof the drying device. Such dampening device serves to restore the normalmoisture contents of the sheets which tend to be reduced to a certainextent by heating of the sheets during the drying operation. Thedampening means may be located closely adjacent to the cooling means ofthe drying device.

Further cooling of the sheets may be efiected by one or several cooleddrums also disposed posterior of the drying device. Such cooled drumseffect a final glazing or smoothing of the sheets.

The conveyor means of the drying device preferably comprise two endlesschain conveyors one carrying the grippers for the leading edge of thesheets and the other carrying the grippers for the trailing edge of thesheets. The respective drive gears for the two conveyors are preferablyangularly adjustable in reference to each other so that the dryingdevice can be set for different sizes of sheets to be dried.

In the accompanying drawing a preferred embodiment of the invention isshown by way of illustration and not by way of limitation.

In the drawing:

FIG. 1 is a diagrammatic elevational side view of a sheet drying deviceaccording to the invention in conjunction with a printing device and asheet laying-out station;

FIG. 2 is a diagrammatic elevational front view of the drying deviceaccording to FIG. 1 as seen from the left side thereof;

FIG. 3 is a plan view of the drying device, partly in section;

FIG. 4 is a fragmentary sectional view of the upper part of FIG. 2 on anenlarged scale; and

FIG. 5 is a fragmentary sectional view of the lower part of FIG. 2 on anenlarged scale.

Referring now to the figures more in detail, the exemplifiedinstallation comprises a diagrammatically shown printing device 1 inwhich the sheets to be dried are printed. The printing device should bevisualized as being conventional and does not constitute part of theinvention.

The freshly printed sheets are transported, one by one, by an alsoconventional conveyor 2 such as a chain conveyor to a drying device 3.The direction of travel of con veyor 2 is indicated by an arrow.

The drying device comprises two conveyor means 9 and 10 such as chainconveyors (FIG. 3). Conveyor means 9 supports gripper shafts 11 whichmount grippers 12 and conveyor means 10 mounts gripper shafts 13 whichmount grippers 14. Grippers 12 serve to grip the leading edge of a sheetto the dried and grippers 14 the trailing edge of the sheet. Thegripping and release action of the grippers is not shown in detail. Itshould be visualized as conventional. The structure of the grippers assuch, does not constitute part of the invention. The spacing of thegrippers 12 and 14 can be adjusted in accordance with the lengthwisedimensions of a sheet (FIG. 2) as will be more fully explainedhereinafter.

Gripper shaft 11 is mounted on outer chains 23 and 24 (conveyor means 9)which are guided over sprocket gears 15, 16 and 17, 18 respectively andare further guided by chain guides 19 and 20. Similarly, gripper shaft13 is mounted on inner chains and 36 which are guided over sprocketgears 27, 28 and 29, 30 respectively and are further guided over chainguides 31 and 32. The correponing sprocket gears of both chain conveyors9 and 10 are mounted on the same shafts 69 and 70 so that they can beangularly rotated in reference to each other as is shown in FIGS. 4 and5.

A sheet is gripped at its leading edge and its trailing edge by grippers12 and 14 when it reaches the device 3 on conveyor 2 and is upwardlyguided along a vertical path. While travelling upwardly, it passes aheating device 39 which may, for instance, direct a hot air flow uponthe passing sheet. Air may be supplied by a pipe 39a.

Stationarily mounted guide bars 40 additionally support the sheetsduring its entire upward and downward travel through the drying device.The guide bars engage the nonprinted side of the sheets or in any event,the dry side thereof. They are secured at one end to U-shaped brackets41 and 42 respectively. The other end of the guide bars is so held thatthe bars can lengthwise expand without being deformed. Moreover, theguide bars are steadied at the upper turn-around of transport conveyors9 and 10 by rotary discs 43.

The sheets after having reached the upper end of the conveyor path areguided downwardly past a cooling de vice 45 in which they are exposed,for instance, to a flow of cool air.

After leaving the cooling device the sheets are guided over water cooleddrums 46, 47 and 48 and finally reach a transport conveyor 38 whichdelivers the now dried and cooled sheets to a laying-out table 49.

While the sheets move over the cooling drums dampeners 50 and 51 directa spray of water upon the side of the sheets opposite to the freshlyprinted but now dried one. The purpose of moistening the sheets afterhaving passed through heating device 39 is to replace the water contentsof the sheets lost in the heating device. The moisture contents of thecool air used in cooling device 45 may be enriched by a water spraynozzle 52 (see FIG. 3) included in a pipe 53 through which air issupplied to the cooling device.

A drive means 4 for driving the conveyor means of the device 3, thecooling drums 46, 47 and 48 and the transport conveyor 38 is coupled toconveyor 2 via gears 55, 56, 57, 58 and 59 housed in a gear box 54.

The drying device is closed off by side walls 60 and 61 which aresecured, for instance, by screws at 62 (see FIG. 3) respectively to anoverhanging part of the frame structure 63 of printing device 1 and toan overhanging part of the frame structure 64 of the sheet laying-outtable 49. Further side walls 65 and 66 of U-shaped cross-section aresecured to side walls 60 and 61 bridging the same.

A heat insulated intermediate wall 68 separates the up and the downpaths of the conveyors, that is, the hot part and the cold part of thedrying device.

As is shown more in detail in FIGS. 4 and 5, sprocket gears 15 to 18 forchain conveyor means 9 are secured on shafts 69 and 70 by pins 71 orother suitable fastening means. Moreover, a sleeve 75 is secured onshaft 69 by pins 74. The sleeve 75 is further secured to gear 15 by oneor several screws 73. Gears 27 to 30 of second chain conveyor means 10are seated on shafts 69 and 70 respectively angularly rotatable inreference thereto. Gears 28 and 27 are fixedly secured to each other bya spacer sleeve 76 and screw bolts 77 and 78. Screw 77 also serves tosecure a spring assembly 79 to gear 27. Similarly, gears 29 and 30 aresecured to each other by means of a spacer sleeve 95 (see FIG. 4). Gears27 and 28 and thus, also gears 29 and 30 are restrained against rotationin reference to shafts 69 and 70 by pressing a bushing 81 against springassembly 79. This bushing is lengthwise slidable on sleeve 75 butsecured against rotation by keys 80. Displacement of bushing 81 towardthe left as seen in FIG. 5 is effected by means of bolts 82 which, inturn, are displaced by the pressure of a bearing sleeve 84. The bearingsleeve is slidable on a trunnion 83 of shaft 69 and also in a bore ofwall 60. It is displaced by means of a spindle 85 having an externalthread 86 engaging a threaded bore of trunnion 83 and a second externalthread 87 engaging an internal thread of bearing sleeve 84. Thread 86has a smaller diameter but a higher pitch than thread 87.

Discs 43 for steadying the guide bars 40 are supported on a spacersleeve 95 supported by shaft 70' as is shown in FIG. 4. The discsinclude cut-outs 96 in which the gripper shafts may be accommodated asthey move in unison with the chain conveyor means. Some of the discs arefixedly secured on the spacer sleeve while others are merely secured bylock rings 88 against axial displacement. Driving dogs 89 effectrotation of those discs that are held in fixed axial positions by rings88.

The possibility of adjusting some of the discs by rotating the same onspacer sleeve 95 allows dimensioning of cut-outs 96 in accordance withthe setting of the distances between gripper shafts 11 and 13 to adaptthese distances to the dimensions of the sheets to be dried.

The chains of both chain conveyors 9 and 10 may be tensioned by a radialdisplacement of a bearing 90 for shaft 70 by turning a spindle 91 whichis rotatable in side wall 60 but secured against lengthwise displacementin reference thereto.

While the invention has been described in detail with respect to acertain now preferred exampled and embodiment of the invention, it willbe understood by those skilled in the art, after understanding theinvention, that various changes and modifications may be made withoutdeparting from the spirit and scope of the invention, and it isintended, therefore, to cover all such changes and modifications in theappended claims.

What is claimed is:

1. A device for drying printers ink on freshly printed sheets, saiddevice comprising in combination:

endless drying conveyor means having a substantially vertically disposedup and down path of travel for drying sheets placed upon the conveyormeans for travelling with the same;

a plurality of first gripper means and second gripper means for grippingthe leading edge and the trailing edge respectively of a sheet fed uponsaid conveyor means, said gripper means being secured to the conveyormeans for travel in unison with the same;

endless transport conveyor means for feeding freshly printed sheets withthe freshly printed side thereof facing upward, one by one, to saiddrying conveyor means at the beginning of the upward path thereof;

second transport conveyor means for transporting sheets arriving at thelower end of the downward path of the drying conveyor means to atreatment station; and

dampening means adjacent to said second transport conveyor means forapplying moisture to the side of the sheets opposite to the freshlyprinted side thereof while the sheets are travelling on said transportconveyor means.

2. The device according to claim 1 and comprising heating means disposedadjacent to the upward path of the drying conveyor means, and coolingmeans disposed adjacent to the downward path of the drying conveyormeans for heat drying and cooling respectively sheets moving along saidpaths.

3. The device according to claim 1, wherein said second transportconveyor means include second cooling means.

4. The device according to claim 3, wherein said second cooling meanscomprise fluid cooled rotary drums.

5. The device according to claim 1, wherein said drying conveyor meanscomprise a first conveyor mounting the first gripper means and a secondconveyor mounting the second gripper means, a pair of shafts, one ofsaid shafts being mounted at the upper end and the other at the lowerend of said up and down paths of the drying conveyor means, and upperand lower pulleys for each of said conveyors seated on said shafts forguiding and driving said conveyors.

6. The device according to claim 5 and comprising setting means forvarying the angular positions of said pulleys in reference to each otherthereby correspondingly varying the relative positions of the first andsecond gripper means to adapt the gripper means positions to differentsizes of the sheets.

7. The device according to claim 5, wherein said first and secondconveyors are chain conveyors and said pulleys are sprocket gears.

References Cited UNITED STATES PATENTS 1,613,445 1/1927 Davis et al.34162 XR 2,174,864 10/1939 Barber 1014l6 XR 2.376,866 5/1945 Butler34162 XR FREDERICK L. MATTESON, ]R., Primary Examiner.

A. D. HERRMANN, Assistant Examiner.

